The scientists said that although their findings are basic in nature, they suggest that the massive amounts of nitric oxide emitted as air pollutants from burning fossil fuels could affect the critical process of plant flowering. Since the decision to flower is so critical to reproduction, a delay in flowering could have important impacts on ecosystems, both plant and animal, they said.
The researchers, led by Duke University biologist Zhen-Ming Pei, published their findings in the Sept. 24, 2004, issue of the journal Science. Co-lead authors were Yikun He and Ru-Hang Tang from Duke. Other co-authors were Yi Hao, Robert Stevens, Charles Cook, Sun Ahn, Liufang Jing, Zhongguang Yang, Longen Chen, Fabio Fiorani and Robert Jackson, all of Duke; and Fangqing Guo and Nigel Crawford from the University of California at San Diego. The research was funded by the National Science Foundation and Duke University.
"The floral decision signaling pathway in plants has been studied for many, many years because the decision to flower is so critical to reproduction," Pei said. "And it was known that some of these pathways integrate external environmental signals, such as daily and seasonal changes in light, while others are autonomous pathways that act independently of external cues.
"However, nobody knew that nitric oxide was involved in these pathways. And nobody knew that plants would be affected by external concentrations of nitric oxide, as might be caused by air pollution." Such biochemical pathways are networks of protein enzymes that make up the signaling machinery that controls the flowering process.